The invention relates to a plate-shaped covering profile which is pressed from a non-risable mixture of fibrous material and a thermosetting binding agent, and provided for covering buildings.
In general, such covering profiles have a body whose upper surface is provided with grooves and that at least one end section of the body is provided with a segment which is arranged offset to the remaining portion of the body. The German Offenlegungsschrift No. 25 30 263 discloses the manufacture of a covering profile for buildings which is pressed out of a mixture composed of fibrous material and a thermosetting binding agent. The so produced construction profile is used as wall and ceiling covering.
Covering profiles are usually used in certain standard sizes, as for example having the size of 20.times.125 cm. The surface of the covering profile which is exposed to the outside is subdivided by a plurality of grooves regularly spaced from each other because of technical reasons and also in order to improve the external appearance. Such covering profiles are applied corresponding to the respective pattern. In case the pattern is covering a large area, a high amount of material is required during the application because the amount of waste is considerable.
Usually, the covering profiles pressed out of a non-swelling mixture of fibrous material and thermosetting binding agent are not produced of such a length which is suitable for the application but of a size multiple of the size of the covering profile ready for application.
The non-swelling mixture is usually composed of lignocellulose-containing fiber material, as comminuted and dried wood chips, bagasse-fibers and the like, which are mixed with a thermosetting synthetic resin, as melamine-ureaformaldehyde resin or phenolformaldehyde resin. Instead of the comminuted and dried wood or bagasse fibers, it is also possible to use fibers of other materials, such as glass fibers, stone wool, or other mineral fibers individually or in any mixture thereof to which preferably organic binding agents are added.
In order to produce a covering profile, the mixture is subjected to a cold pressing for obtaining a prepress article which is subsequently subjected to a hot press and if necessary simultaneously be covered by a decorative cover layer. Within the hot press, the prepress article is shaped to the covering profile which is cured and if necessary simultaneously is completely surrounded by a protective and/or decorative cover layer.
This method of manufacture, however, has the disadvantage that the covering profiles which are provided with transverse grooves regularly spaced on the exposed surface thereof become distorted or warped. Moreover, the manufacture of such covering profiles is additionally impaired because the prepress article is swelling by a certain volume after its removal from the prepress. The quantity of this increase in volume is not constant, but depends on a number of parameters, for example the shape of the fiber material, the fraction of binding agent in the non-swelling mixture, the moisture degree of this mixture, the applied manner for filling the mold with the mixture, the period of the prepressing step, and the interim period between prepressing and hot pressing.